Many drugs, dyes, and similar aromatic compounds bind to nucleic acids, and this interaction is related, in most cases, to their actions as antitumor agents, mutagens, antimicrobials, and stains. Intercalation of planar aromatic compounds between base pairs of the DNA double helix is a generally accepted binding mechanism, but much of the evidence for it is indirect, and relatively few of the details of the interaction have been elucidated. The purpose of this study is to obtain geometrical and kinetic parameters of oligonucleotide-dye complexes and to use these data to evaluate intercalation and other models of DNA-drug binding. This will be done by synthesizing acridine, phenazine, and triphenylmethane dyes containing covalently attached groups that can chelate a variety of metal ions. The dye moieties have been chosen from those that are throught to bind externally, and/or by intercalation into the DNA double helix; the metal ions have been selected on the basis of their ability to shift and/or broaden NMR signals. The complexes resulting from the interaction of these paramagnetic metal-containing dyes with various oligonucleotides will be studied by NMR spectroscopy. By measuring the extent of the perturbation of the nucleotide resonances caused by the dye-carried metal ions, it will be possible to calculate angles and distances between perturbed nuclei and the metal. In addition, the metal chelate dyes synthesized for the above study will be evaluated as cytochemical stains in collaboration with workers. By using an electron dense metal, a reagent suitable for electron microscopy should be obtained, the usefulness of which should be greatly enhanced by the base-pair specificity inherent in the dye portion of the chelate.